In the process of production of various electronic devices such as semiconductor integrated circuit devices (below, also simply referred to as DUTs (devices under test)), an electronic device test apparatus is used to test the DUTs for performance and function. This electronic device test apparatus comprises: a tester body sending a test signal to a DUT and inspecting a response signal; a test head connected to this tester body and having a socket for electrically contacting the DUT; and a handler successively conveying DUTs over the test head and classifying DUTs finished being tested according to test results. Tests by this electronic device test apparatus are conducted in a state with the handler giving the DUT a high temperature or low temperature thermal stress.
The test head of such an electronic device test apparatus comprises a large number of pin electronics cards used as electrical interfaces between DUTs and the tester body. Each of the pin electronics card comprises a board on which a large number of test use high frequency circuits, power circuits, and various other types of test devices are mounted.
Among the test devices mounted on the pin electronics cards, there are ones which become high in temperature when testing the DUTs due to their self generated heat. As opposed to this, in order to cool the test devices becoming high temperature due to the self generated heat by direct immersion in a coolant, a water jacket covering the test devices mounted on the pin electronics card has been conventionally known (for example, see Patent Citations 1 and 2).
In the above water jacket, the channel through which the coolant runs has a constant flow passage sectional area. For this reason, when the flow volume of the coolant supplied to the water jacket is limited to a certain volume, there has been a limit to the improvement of the cooling efficiency.
[Patent Citation 1] Japanese Patent Publication (A) No. 10-51169
[Patent Citation 2] Japanese Patent Publication (A) No. 10-303586